Fingerprints are impressions made by the ridges on the ends of the fingers and thumbs that are unique for every human being, even identical twins.
These ridges do not change with growth or age. Superficial burns, cuts and scrapes do not affect fingerprints as the original pattern is maintained when the new skin grows. Only severe injury or surgery will alter fingerprints.
General characteristics of fingerprints help classify them into different types based on the three basic features of loops, arches and whorls. These general characteristics can be inherited, therefore family members do tend have similar fingerprint patterns.
John Edgar Hoover was director of the FBI for almost 48 years. He was responsible for establishing one of the best forensic laboratories in the world, as well as a national fingerprint register. The FBI's fingerprint and background data base is the largest one in the world. 
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